Calculate the velocity of motors DC with 1746 HSCE

[zaranet]

when you devide I:2.1 by 1250, you have number the tr of encoder so number the tr the motor

 

[Eric Nelson]

I still do not know what you mean by "tr".

Possibly "turns"?...



-Eric

 

[leitmotif]

Possibly "turns"?..-Eric

Zaranet

I say again while there is a language difficulty do not be embarassed. We would not do any where as well in your native tongue as you are in English. We can deal with the language
BUT
we are confused as to what tr means
you at least need to help us and use common engineering and electrical terms.

I am going to ad - what is "tr". Revolutions RPM radians OR??

Dan Bentler

 

[zaranet]

Tr is revolution radian of the motor or the encoder
for example we can say the velocity of this motor is 1500tr/mn at the moment the motor have 1500 turn for 1 minute

 

[leitmotif]

Tr is revolution radian of the motor or the encoder
for example we can say the velocity of this motor is 1500tr/mn at the moment the motor have 1500 turn for 1 minute

Zaranet

OK so you are measuring revolutions in radians.
One revolution = 6.28 radian
Taking your example but changing RPM to 1000 to make math easier
1000 RPM = 6,280 radian / minute

Dan Bentler

 

[Imi'ike]

So...how did the little test of moving the motor one revolution and comparing that the to the contents of I:2.1? When you move the motor you could do it by hand, you do not need to power it.

Or, is everything fine now and you are on your way?

As for your scale factor. 1250 counts/revolution * 1 revolution / 6.28 radians = 199.045 counts/radian. So again, if I:2.1 is divided by this scale factor (199.045) then you should be all set with reading the encoder and displaying it in "tr". You will need to provide us with feed back on this.

 

[zaranet]

with all that, i am very pertubing and i don't know how can i do it;
my motors velocity is 740tr/mn
and my encoder revolution is 1250 for tr
and I think that i devide I:e.3 by 199.05 and i obtain the velocity in units rd/s

 

[Imi'ike]

The reason I asked you (twice now) to give the motor one revolution and then compare that to the contents of I:2.1 divided by the scale factor is so that you can know if you have the correct scale factor. So please do the test. Do you understand the point of this?

So with a little more detail:
1) Read the value (contents) of I:2.1 and write it down. This is the initial count
2) Move the motor one revolution. Do this by hand, do not run it electrically unless you can move one and only one revolution.
3) Read the new value of I:2.1 and write it down. This is the final count.
4) Subtract the final count from the initial count and divide by your scale factor. i.e.:
{(final count) - (initial count)} / (scale factor)

This value should be the same number of "tr" that you physically moved the motor. If it is, great! You can move on to velocity. If not, then you need to get your scale factor correctly calculated before you move on to velocity.

If not, then I suspect you need to understand how you are using your encoder: quadrature (4x), or 2x, or 1x. You also need to understand the mechanical linkage between the encoder and the motor and the device that is driven. Let's say you are actually configured for quadrature. This means you have 4 counts per pulse (of the encoder). You still have 1250 pulses per revolution and 1 revolution has 6.28 radians (or tr?). Then your scale factor would be:

[4 counts / pulse] * [1250 pulse / revolution] * [1 revolution / 6.28 radians] = 796.178 counts/radian

Do you understand the difference between the two scale factors that we have calculated?

Oh, I do not understand the point of your text in red. If it is a question, then the answer is yes.